Re: [PATCH v2 09/23] x86/resctrl: Switch over to the resctrl mbps_val list

From: Reinette Chatre
Date: Fri Oct 15 2021 - 18:27:08 EST


Hi James,

On 10/1/2021 9:02 AM, James Morse wrote:
Updates to resctrl's software controller follow the same path as
other configuration updates, but they don't modify the hardware state.
rdtgroup_schemata_write() uses parse_line() and the resource's
ctrlval_parse function to stage the configuration.

parse_ctrlval ?

resctrl_arch_update_domains() then updates the mbps_val[] array
instead, and resctrl_arch_update_domains() skips the rdt_ctrl_update()
call that would update hardware.

This complicates the interface between resctrl's filesystem parts
and architecture specific code. It should be possible for mba_sc
to be completely implemented by the filesystem parts of resctrl. This
would allow it to work on a second architecture with no additional code.

Change parse_bw() to write the configuration value directly to the
mba_sc[] array in the domain structure. Change rdtgroup_schemata_write()

mpbs_val[] array?

to skip the call to resctrl_arch_update_domains(), meaning all the
mba_sc specific code in resctrl_arch_update_domains() can be removed.
On the read-side, show_doms() and update_mba_bw() are changed to read
the mba_sc[] array from the domain structure. With this,

mbps_val[] ?

Should rdtgroup_size_show() also get a similar snippet?

Reinette